Spirit Varnish for Violins

Today I mixed some new varnish, Apothecary style on a real old balance scale, with the traditional resins and gums. On the left scale you can see benzoe and mastix and on the right, sandarac. I'd already measured the shellac into the large glass jar which is flanked by gum elemi on the left and venetian turpentine. Behind is a 5l container of spirits, 99.7% ethanol to be exact.

Benzoe: is a balsamic resin which comes from one of several species of Styrax trees. It has the most wonderful smell, which is why I like to use it. So not surprsingly it is also used to make incense, and as a fixative in perfumery.

Mastix: comes from the sap of the tree pistacia lentiscus. As well as being one of the finer resins to use for violin varnish it is used as a culinary spice in Greece and Turkey, especially for sweets and desserts and is also a kind of natural chewing gum. Probably the best thing is to pick the resin drops straight off the tree, if you're going to use it as chewing gum, because I find that it tends to crumble in the mouth and then stick stickily on the teeth, but it has a lovely flavour and apparently soothes the stomach, absorbs cholesterol and reduces bacterial plaque (by 41,5% according to one study).

Sandarac: is a resin from North African tetraclinis articulata. It is one of the most important ingredients in varnish but also used as incense, a remedy for diarrhea, and calligraphers like to grind it up and sprinkle it on their parchments.

Shellac: is a resin which doesn't come directly from a tree, but via the alimentary canal of the female lac bug kerria lacca. The rather pale shellac that I use (there are many different colours) probably comes from the tree schleichera trijuga. It's fairly common knowledge that shellac is used as a varnish and as an ingredient in a french polish, but it is also known as food additive number E904 and used to replace the natural wax removed from apples during the cleaning process! It is also a low temperature fuel which allows for the creation of pures greens and blues in fireworks.

Gum elemi: This is a fragrant sticky mess which comes from the tree canarium luzonicum. It can been used to treat coughs and brochitis and in Arabic it means "as above, so below" suggesting that it works on the emotional and spiritual planes as well.

Venetian turpentine: is a variety of turpentine that comes from the Western Larch or larix occidentalis. Ordinary modern turpentine is a horrid stinky liquid used for cleaning brushes and things, but it has traditionally been used in medicine to treat wounds, lice and intestinal parasites and is still used as an ingredient in Vicks chest rub.

Very pretty when the jar is filled with alcohol and put in the window, though not for long as they all start to mix and dissolve and murkify. I'll stir it now and then and when I'm happy, filter it through an unbleached coffee filter to remove the insoluble bits.

So you want to know the secret of my varnish? The secret is that there is no secret. It's my own concoction based largely on what we used at school and I'm quite happy with the way it works. Here is the recipe:

  4 parts sandarac
  2 parts shellac
  1 part benzoe
  1 part mastix
  1 blob gum elemi
  1 blob venetian turpentine

Raising the saddle on a double bass to lessen the string angle.

A problem that you sometimes get with basses is that the angle of the strings at the bridge is too acute. This is idiosyncratic to the way the instrument, in particular the neck setting, has been constructed. The steeper the angle of the strings at the bridge, the more downwards pressure is exerted on the table. This can affect the tone and may result in a bigger, brighter sound which could be desirable, but it can also cause problems if the table is old, thin and/or pressure sensitive. One may also be looking for a warmer, more open response for orchestra playing.

The solution to this problem, if it is a problem, is to raise the height of the bottom saddle. There are a variety of ways to do this and many players are now looking for an adjustable saddle raiser which allows them flexibilty, for them to have more control over the instrument's sound. I have just had a bass in for that job and came up with the solution pictured above. I am quite pleased with the result: a simple, what they might call here in Sweden "funkis", design. It is made from an old piece of fingerboard, fitted exactly to the existing saddle, which has two invisible screws holding it in place. It sits loosely and may easily be removed should the player wish to return to the original setting. The pressure from the string tension here is quite enormous which means careful attention to the fitting and form of the saddle is essential. The laws of physics and mechanics (vectors) must be taken into consideration. The tailwire is made of a very strong, non-elastic cord, tied with a simple knot which can also be easily adjusted. This will be necessary when switching between the different saddles. 

Here you can see the adjusted string angles which sit nicely and evenly over the bridge.

Double basses and winter humidity issues

We are experiencing an unusually long and cold winter this year, and in my workshop there is a queue of cracks and buzzes to be attented to. Humidity levels in winter and how they relate to instrument care is something I spend a lot of time discussing with customers. My own opinion is not necessarily gospel truth and I'm still collecting data - when it comes to basses it's an inexact science - but this is what I have to say.

Relative humidity: Cold air cannot hold nearly as much moisture in it as warm air. What happens in winter is that cold air from outside, which contains low but relatively speaking quite acceptable moisture levels, comes into our living spaces and is warmed up by our heating systems. While the actual amount of moisture in the air remains constant the warm air is now relatively speaking very dry and this can cause problems with musical instruments.

What dry air does to your instrument:

Wood: When wood dries out it shrinks, mostly between the grain lines. This means that when you look at the table of your instrument, with the grain lines running down the length of the instrument, the width will decrease slightly over time. If it shrinks too fast a crack could pop open running along the length of a grain line. What compounds the problem is that the instrument is constructed in such a way that the grain lines in the ribs, table and back run in different directions, so that when shrinkage occurs it creates tension in the instrument. What can then happen is that the ribs, which shrink along their width much more than their length, become too long for the shape of the table and pop out of line. Added to this is the fact that a many basses are made from wood that is at least partially slab cut (you can see this in the pretty circular grain patterns in the upper and lower bouts). This can create a tension which pushes the two edges of a crack out of alignment, making a straight forward gluing job impossible. Wood that has been well seasoned will present with fewer problems.

Glue: Dry air also affects the hide glue used in instrument making. This is less serious. The glue shrinks as it dries, bringing the two sides of a joint tightly together. Moist glue is quite elastic, but it become more brittle as it dries. This means that in dry conditions seams of glue can become so brittle that they open up, usually between the ribs and table or ribs and back. This is easily rectified.

String height: On some instruments the string height changes with the season, so that the strings end up lying too far or too close to the fingerboard, affecting playability. An adjustable bridge or summer/winter bridges is usually the answer to this. Some instruments need a higher bridge in the winter, some need a lower bridge, and many are quite stable and don't need adjustment at all. I have not yet found rhyme or reason why this is so. There are just too many varying factors involved. Wood is a very complex material and behaves in a unique manner in each instrument. On instruments that do change a lot seasonally it is a good idea to keep an eye on the tightness of the sound post. Some instruments need different length sound posts for different seasons both sound wise and as insurance against possible sound post cracks.

Humidity control for bass owners

We have several hygrometers (humidity gauges) in the workshop and they all show different measurements. There are ways to callibrate them, but it's important to realise that they can be unreliable. Luckily we humans, like our basses are also sensitive to humidity levels. If you feel the dryness in your nose and your lips, you know that you need to need to do something about the humidity for your own sake as well as your bass's.

Room humidifiers: This was one of the first thíngs I invested in, but it made so little difference to the humidty in the workshop that I just returned it. There are simpler methods which I use e.g keeping water containers by every radiator. When the temperature drops below minus ten outside I start boiling water in the kettle with the lid off 10 mintues at a time and I'll have a steaming pot of water on the stove all day (which I use anyway for glue). The cheaper humidifiers available may be sufficient for a small room, and I'm sure that there are sophisticated expensive ones available too which would be effective. I'd be interested to hear of other people's experiences.

"Dampits": I'm not a "dampit" fan. The danger with them is that they drip water inside the bass which leaves stains in the wood and mixes with the dust inside to form a kind of cement which is a nuisance to clean. The drops of water can also dissolve glue and seams can open. As general rule when it comes to drying or moistening wood, the slower the better. The structure of the wood can be damaged both when the cells collapse suddenly due to harsh drying and when the cells expand suddenly when water is dropped on them. So if you use "dampits" make sure that you wipe off the drips. Otherwise just keep your bass inside its cloth cover when you're not playing.

What to do about cracks and buzzes:

Open seams and some cracks are easily fixed with a bit of warm hide glue and a clamp. For others it may be necessary to open the bass so that they can be properly glued and reinforced. Sometimes I'll choose to leave a crack open until a later time when the instrument can be opened. Some cracks can be glued provisionally and then reinforced from the inside at a later date. Some cracks will create a buzz, some won't affect the sound at all. Some are really obviously, others are quite secretive. Buzzes are a whole mystery in themselves and can have many different causes. If you find a crack or open seam on your instrument that does not affect its playability, it can be left until a convenient time to fix, say within a few months or so, depending. But if it is left too long there is a danger that it can get worse if it has been caused by tension and it can also collect dirt and be more difficult to fix invisibly. 

So my advice to players is check your instrument reguarly and bring it in if you have questions, to me or another repair person whom you trust. What I have written here is as much as I can say without actually looking at your instrument together with you.

Changing strings

This is something that players usually do themselves, which is good, because it's not one of my favourite jobs. Unfortunately I'm often confronted with some odd spaghetti tangles and end up having to redo it anyway. So here's a quick tutorial:

There are several different methods, but this one is easy. It may look a bit odd with the long tails, but these can be trimmed with a pair of wire cutters if desired. They are however useful as when you want to remove the string, all you need to do is loosen the tension and then thread the tail back through the hole and you've saved yourself an awful lot of winding. To put on a new string thread it through the hole leaving a longer tail for a shorter mensure (vibrating string length) and a thinner cone. Wind once around the inside and then aim for 2 to 4 windings on the outside, depending on the thickness of the string and the distance of the hole to the peg box wall - as you can see in the picture. Hold the string taut with one hand while winding with the other. This makes the windings much neater and gives you a better idea of how much tail to leave. It's good when there are enough windings for the string to lie snugly against the wall of the peg box.

• Avoid letting the windings cross over each other.
• Avoid taking off all the strings at once as the bridge and maybe also sound post will come loose.
• Change the outer 2 strings first followed by the inner strings, it's easier that way and the tension is more even on the instrument.
• Keep an eye at all times on the bridge. It has a tendency to lean up towards the fingerboard as the strings are being tightened. Just press it back into place if this happens.
• It can also be a good idea to lubricate the string grooves at the bridge and saddle with an ordinary graphite pencil.

If you have a string that you can see is a bit short just thread the string through the hole, wind once and then thread the end of the string over the winding, back through the hole and carry on tuning up.